Current-based Techniques for Condition Monitoring of Pumps

[ES] Las bombas hidráulicas son el núcleo de muchos procesos en la industria y el sector servicios. Conviene tener en cuenta que los motores eléctricos son responsables del 69% del consumo de energía eléctrica en la industria, siendo en torno a un 22% de motores utilizados para el accionamiento de bombas. Los fallos de estas bombas pueden provocar averías en el proceso y, por lo tanto, implican altos costes económicos para el operador de la planta. Además, un funcionamiento defectuoso de las bombas conlleva una reducción de la eficiencia energética de la planta. De forma habitual, se utilizan principalmente dos tipos de estrategias orientadas al mantenimiento de maquinaria. Una estrategia de mantenimiento (mantenimiento preventivo) consiste en la sustitución de las piezas desgastadas en un intervalo de tiempo fijo. Este tipo de estrategia presenta muchas desventajas asociadas a la escasa optimización en el uso de los recursos y al consiguiente impacto económico. Por otro lado, la estrategia basada en la condición del equipo (mantenimiento basado en la condición) liga el reemplazo de las piezas desgastadas al estado del equipo, el cual es monitorizado a través de señales adquiridas mediante sensores. Sin embargo, el uso de sensores tiene algunos inconvenientes, como costes de inversión adicionales, posibles problemas en el montaje del sensor y posibles fallos del mismo. El análisis de la señal de corriente no se ha utilizado de forma habitual en la práctica para evaluar el estado de la bomba, aunque en muchas aplicaciones se dispone de sensores de corriente ya instalados que se podrían utilizar a tal fin. Se ha demostrado que técnicas basadas en el análisis de la corriente resultan de gran utilidad para diagnosticar varios tipos de fallos en motores eléctricos. De hecho, el análisis de la firma de corriente del motor se utiliza hoy en día ampliamente en la industria, especialmente para el diagnóstico de fallos en motores de inducción. En la presente tesis, se evalúa la utilización de la técnica de análisis de corrientes para el diagnóstico de fallos típicos relacionados con las bombas en diferentes aplicaciones. Se investigan tres tipos de bombas diferentes: bombas en línea de rotor húmedo, bombas de rotor seco y bombas sumergibles. En la tesis se han adaptado diversas técnicas, previamente empleadas para la detección de fallos en motores, al diagnóstico de fallos en la propia bomba. Los resultados indican que fallos como obstrucción de la bomba, fisura del impulsor y desgaste de los cojinetes influyen especialmente en dos frecuencias del espectro de corriente, las cuales pueden utilizarse como base de estrategias de mantenimiento basadas en la condición. En concreto, en las bombas de rotor húmedo, estos dos indicadores de fallo varían sensiblemente en función del punto de carga hidráulica de la bomba. Con la ayuda de un método de extracción de características basado en la motor reference frame theory, se demuestra que las mencionadas frecuencias pueden analizarse en tiempo real en un entorno industrial. Además, se presentan directrices para la monitorización en la nube y se valida con la ayuda de ensayos de laboratorio. Adicionalmente, se demuestra que los fallos son también detectables al analizar la corriente de arranque mediante herramientas de descomposición tiempo-frecuencia. Este hito no se había abordado anteriormente en la literatura técnica del área en lo referente a la detección de fallos en bombas. En conclusión, los resultados de este trabajo demuestran que los métodos de diagnóstico basados en la corriente pueden detectar con éxito diversos tipos de fallo en bombas, lo cual constituye un punto de gran interés para las industrias que utilicen estos activos en sus procesos.[CA] Les bombes hidràuliques són el nucli de molts processos en la indústria i en el sector dels serveis. Cal mencionar que els motors elèctrics són responsables del 69% del consum de la energia elèctrica en la indústria, sent al voltant del 22% dels motors utilitzats per l'accionament de bombes. Les fallades d'aquestes bombes poden causar avaries en els processos, i per tant, representen un alt cost econòmic per a l'operador de la planta. A més a més, un funcionament defectuós en les bombes representa una reducció de l'eficiència energètica de la planta. De manera habitual, s'utilitzen principalment dos tipus d'estratègies orientades al manteniment de la maquinària. Una estratègia de manteniment (manteniment preventiu) consisteix en la canvi de les peces desgastades en un interval fixe de temps. Aquest tipus d'estratègia presenta molts desavantatges associats a la reduïda optimització en el ús dels recursos i el seu impacte econòmic. D'altra banda, la estratègia basada en la condició dels equipaments (manteniment basat en la condició) enllaça la substitució de les peces desgastades al estat de l'equip, el qual es monitoritzat per mig de senyals adquirides per sensors. No obstant això, el ús de sensors té alguns inconvenients com costos d'inversió addicionals, possibles problemes al muntatge i possibles fallades. L'anàlisi dels senyals de corrent no s'utilitzen de manera habitual en la pràctica per avaluar l'estat de la bomba, encara que en moltes aplicacions, estos sensors es troben instal·lats i es podrien fer servir per a aquesta finalitat. Ha estat demostrat que les tècniques basades en l'anàlisi de la corrent són de gran utilitat per el diagnosi de diversos tipus de fallades en motors elèctrics. De fet, l'anàlisi de la firma de la corrent del motor s'utilitza àmpliament en l'indústria, especialment per el diagnosi de fallades en motors d'inducció. En la present tesi, s'avalua l'utilització de la tècnica d'anàlisi de corrents per el diagnosi de fallades típiques relacionades en bombes per a diferents aplicacions. Se investiguen tres tipus de bombes diferents: bombes en línia de rotor humit, bombes de rotor sec i bombes submergibles. En aquesta tesi se han adaptat diverses tècniques, prèviament utilitzades en el diagnosi de màquines elèctriques, per al diagnosi de la pròpia bomba. Els resultat indiquen que les fallades com obstrucció de la bomba, la fissura de l'impulsor i el desgast dels coixinets influeixen especialment en dos freqüències de l'espectre de la corrent, les quals es poden utilitzar com a base per a una estratègia de manteniment basada en la condició. Particularment, en les bombes de rotor humit, aquestos dos indicadors de fallada varíen sensiblement en funció del punt de càrrega hidràulica de la bomba. En l'ajuda de un mètode d'extracció de característiques basat en la "motor reference frame theory", es demostra que les mencionades freqüències es poden analitzar en temps real en un entorn industrial. A més a més, es presenten directrius per la monitorització en el núvol i es valida en l'ajuda de assajos en el laboratori. Addicionalment, es demostra que les fallades són també detectables quan s'analitza la corrent d'arrancada mitjançant ferramentes de descomposició temps-freqüència. Aquest fet no ha estat analitzat prèviament en cap tipus de literatura tècnica dins del camp de detecció de fallades en bombes. En conclusió, els resultats d'aquest treball demostren que els mètodes de diagnosi basats en la corrent poden detectar en èxit diversos tipus de fallades en bombes, el qual constitueix un punt d'interés per a l'indústria que utilitzen aquest tipus de actiu en els seus processos.[EN] Pumps are the heart of many processes in industry and service sector. Electric motors are responsible for 69% of electric energy consumption in industry, with 22% of them being used for the operation of pumps. Pump faults can lead to process breakdowns and are thus related to high costs for the plant operator. Furthermore, faulty operation of pumps reduces the energy efficiency of the plant. In many cases, a time-based maintenance strategy is applied, which means that typical wear parts are replaced within defined time cycles, which comes with some drawbacks such as poor resource efficiency and high costs. Condition-based maintenance strategies - meaning that the replacement of parts is planned based on the condition of the pump - are often based on the evaluation of sensor signals like vibration or noise. However, the use of sensors also has some drawbacks, such as additional investment costs, frequent problems with the sensor mounting, and possible sensor faults. There is no widespread use of the current signal to make statements about the pump condition, although current sensors are installed in many applications anyway. As for motor fault diagnosis, different current-based techniques have demonstrated their function. Today, motor current signature analysis is used in industry, especially for the diagnosis of induction motors. In this thesis, the current-based diagnosis of typical pump-related faults in different applications is evaluated. In total, three different pump types are investigated: a wet-rotor pump, a dry-runner inline pump, and a submersible pump. The techniques used for motor fault detection are adapted for the diagnosis of pump-related faults. The results indicate that the faults clogging, impeller crack, and bearing wear, in particular, influence two frequencies in the current spectrum, which can be used as a basis for a condition-based maintenance strategy. Especially in wet-rotor pumps, these two fault indicators strongly vary depending on the hydraulic load point of the pump. With the help of a feature extraction method based on the adapted reference frame theory, this work demonstrates that the two frequencies can be analyzed in real time in a field environment. Furthermore, a concept for cloud monitoring is presented and validated with the help of a laboratory test. Additionally, it is demonstrated that the faults are visible if the starting current is evaluated in a time-frequency map, which has not been considered before in the literature on pump-related faults. In summary, the findings of this work indicate that current-based diagnosis methods can successfully detect typical faults in pumps, a fact that is of high interest for companies using these assets in their industrial processes.Becker, V. (2022). Current-based Techniques for Condition Monitoring of Pumps [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/19063

Catastrophic medical events with exhaustive exercise: “White collar rhabdomyolysis”

Each year, especially in the United States, young and middle aged men die from a variety of causes during or following intense physical exertion. For unknown reasons, death and disability as a consequence of physical effort are virtually unknown in women, despite the fact that they participate heavily in competitive sports.The most important complications of exhaustive exercise are shown in Table 1. Of these, rhabdomyolysis, especially if associated with exertional heat stroke, is one of the most devastating clinical illnesses that exists. The term rhabdomyolysis defines an injury to skeletal muscle cells of such severity that their contents leak into the circulation. The injury may be confirmed biochemically by demonstrating elevated concentrations of enzymes in serum that are specifically located in skeletal muscle cells (CK-MM, aldolase) or myoglobin. Myoglobin released into the circulation is filtered and excreted into the urine, so-called myoglobinuria. The latter invokes the risk of acute renal failure (pigment nephropathy). Exertional rhabdomyolysis is an exceptionally common event. It is probably experienced in mild form by everyone who has undergone some form of exercise training during their youth when it is expressed simply by stiff and tender muscles. If at that time someone happened to measure a serum CK value, it would be slightly to modestly elevated. Some of the most classic examples of frank exertional rhabdomyolysis occur among our most highly trained endurance runners. In the majority of cases, there is no history or other apparent evidence for myopathy before the event. In most who survive major episodes, subsequent muscle testing has shown no results that suggest a hereditary myopathy such as McArdle's Syndrome, carnitine palmityl transferase deficiency, or other myopathy. Because of this, it is assumed that any normal person may develop frank rhabdomyolysis provided the provocation is adequate. Provocative events consist of exhaustive exercise, especially when competitive, and particularly if the athlete musters his supreme effort to win during the last segment of a race. Hot or warm weather and a high relative humidity increase the risk enormously. Victims of this disorder often give a history that they continued to run despite cramping pain and “dead legs”. Some of them continue to run despite obvious disorientation and confusion. Observers commonly recall that victims appeared pallid or gray as if their skin vessels had become constricted as a result of a massive discharge of norepinephrine or alternatively, their cardiac output and peripheral circulation had failed. It seems that it is this last burst of effort that often provides the coup de grace, so that the patient develops major and widespread soft tissue injury and in some cases, heat stroke as an associated illness.It is unfortunate that the gravity of acute exertional rhabdomyolysis is so often unappreciated by physicians who initially provide care for these patients. Although the victim may collapse and appear to recover quickly, in some of these, potentially fatal metabolic acidosis, hyperkalemia, disseminated intravascular coagulation and the acute respiratory distress syndrome may appear during the following 24 hours. The syndrome of rhabdomyolysis is given little attention in the major textbooks of internal medicine. Perhaps this is one of the reasons why the gravity of the illness is so commonly unappreciated at the onset when appropriate identification and treatment of its complications could be life saving.There is strong evidence that training induces a degree of resistance to development of exertional rhabdomyolysis as well as exertional heat stroke. Some of this evidence will be reviewed, but with emphasis on the fact that even a highly trained athlete can still develop exertional rhabdomyolysis. Following the review of the physiological mechanisms that help forestall injury incident to exertion, several cases will be presented that will highlight some of the devastating complications of exercise

MIXED-FLOW PUMP OPTIMISATION AND FLOW CHARACTERISTICS BASED ON THE ‘DUAL CARBON’ GOALS

Urban water supply and drainage, the shipbuilding industry, the petrochemical industry and other professional fields rely heavily on mixed-flow pumps. Enhancing the efficiency of mixed-flow pumps is crucial for achieving the ‘dual carbon’ goals and promote energy saving and emission reduction. In this study, the guide vane and impeller of the mixed-flow pump were optimised, focusing on its low head and effectiveness in power plants. The performance of the original and optimised pumps was then evaluated under various flow rate conditions, and their hydraulic performance was compared. Results showed that the efficiency of the optimised mixed-flow pump was improved, resulting in effective enhancement of energy loss in the pump passage. The optimised guide vane facilitated smoother water flow into the outlet pipeline, achieving energy savings, emission reduction and contributing to the realisation of the ‘dual carbon’ goals

Experimental and CFD Simulation of a Multiphase Canned Motor Pump

Canned motor pumps are well suited for pumping hazardous and radioactive fluids due to their compact design and low maintenance cost. However, their application on artificial lift has not been investigated yet. ESP (Electric Submersible Pump) has been used as an artificial lift method for pumping high volume flow rate in deep wells. However, due to its seal leaking and bearing abrasive problems, pump performance is deteriorated during operation. This work investigated utilizing a canned motor pump instead of ESP in downhole application. The performance of a canned motor pump under multiphase flow was studied experimentally and computationally. A canned motor pump demonstrator manufactured by Curtiss-Wright EMD was installed in the pump test loop built at Turbomachinery Laboratory at Texas A&M University. The water baseline performance test and multiphase flow (water/air) test was performed. GVF (Gas Volume Fraction) in pump stator jacket was varied from 0% to 20%, and the pump speed varied from 2000 RPM to 3930 RPM. The pump’s performance at these flow conditions was recorded and learned. The air inside the bearing house and rotor-stator annulus causes cooling and lubrication problems for normal pump operation. The air distribution of the secondary circulation flow inside the pump is the main concern. Thus, multiphase flow inside the pump was simulated with CFD commercial code, ANSYS Fluent. Different GVF with different water flow rate was simulated. Also, pressure at flow region outlet and bubble diameter effect were also simulated. Flow rate distribution trend predicted by CFD method is validated by experimental test results. Impedance probe was designed and built to measure multiphase flow in a pipe. The GVF is the main calibrated parameter. The fluid’s dimensionless admittance was found to have linear correlation with GVF. The phase of CPSD from probe’s signal is a promising calibration tool for the future probe application

Experimental and CFD Simulation of a Multiphase Canned Motor Pump

Canned motor pumps are well suited for pumping hazardous and radioactive fluids due to their compact design and low maintenance cost. However, their application on artificial lift has not been investigated yet. ESP (Electric Submersible Pump) has been used as an artificial lift method for pumping high volume flow rate in deep wells. However, due to its seal leaking and bearing abrasive problems, pump performance is deteriorated during operation. This work investigated utilizing a canned motor pump instead of ESP in downhole application. The performance of a canned motor pump under multiphase flow was studied experimentally and computationally. A canned motor pump demonstrator manufactured by Curtiss-Wright EMD was installed in the pump test loop built at Turbomachinery Laboratory at Texas A&M University. The water baseline performance test and multiphase flow (water/air) test was performed. GVF (Gas Volume Fraction) in pump stator jacket was varied from 0% to 20%, and the pump speed varied from 2000 RPM to 3930 RPM. The pump’s performance at these flow conditions was recorded and learned. The air inside the bearing house and rotor-stator annulus causes cooling and lubrication problems for normal pump operation. The air distribution of the secondary circulation flow inside the pump is the main concern. Thus, multiphase flow inside the pump was simulated with CFD commercial code, ANSYS Fluent. Different GVF with different water flow rate was simulated. Also, pressure at flow region outlet and bubble diameter effect were also simulated. Flow rate distribution trend predicted by CFD method is validated by experimental test results. Impedance probe was designed and built to measure multiphase flow in a pipe. The GVF is the main calibrated parameter. The fluid’s dimensionless admittance was found to have linear correlation with GVF. The phase of CPSD from probe’s signal is a promising calibration tool for the future probe application